This invention relates in general to sewing machines and in particular to a new and useful drag clamp mechanism for holding a plurality of plies of material of a workpiece to be sewn as it is fed by a sewing machine feeding mechanism past the cooperating reciprocating needle and rotary hook located in a stitch forming area.
A sewing mechanism similar to the inventive mechanism is disclosed in German Pat. No. 27 28 967. In this prior art arrangement, as soon as the drag clamp approaches the contour control device, the contour control device is retracted from the path of motion of the drag clamp, so that the drag clamp can move with the fabric close up to the presser foot of the sewing machine. It is true that in this way, the fabric ply ends remain clamped up to close to the stitch forming area and are thus secured against mutual displacement in the sewing direction. However, due to the retraction of the contour control device, the side edges of the fabric plies are no longer guided laterally in the last seam portion which still has an extension of several centimeters. This entails a chance that in spite of the clamping of the fabric ply ends by the drap clamp, the fabric ply side edges of the last seam portion will not be sewed together in register.